[Cookbook][Forms] fix PHP template file name
bug #4103 [Cookbook][Forms] fix PHP template file name (xabbuh)

This PR was merged into the 2.3 branch.

Discussion
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[Cookbook][Forms] fix PHP template file name

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | all
| Fixed tickets | part of #4088

Commits
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6a14650 [Cookbook][Forms] fix PHP template file name